[Radioroslyn]

Ok so let's name the players. C-1 connects across the primary of the transformer. C-2 connects signal from the plate of the 6SB7Y to the secondary of the transformer. C-3 and C-4 create a capasitive tap to feed in signal into L-2. L-1 primary and L-2 secondary.

C-3 and C-4 are probably going to out of the equation as without C-1 or C-2 running afoul there wouldn't be any hv over there. C-1 is in parallel with L-1. It helps determines the resonate frequency along with the slug adjustment. It occurs to me that all four caps are part of that copper board cap and that all of it is going to go. C-3 and C-4 total are going equal about C-1 maybe 10-20mmf. C-2 is probably is going to be a bit smaller in value perhaps 5-10mmf. You may be able the measure them with a cap meter or check resonant frequency with GDO old skool...

ps Didn't see Rod's post so values are probably more realistic than my guesses.